Plastics in Agriculture – An Environmental Challenge
July 2022 | United Nations Environment Programme
Background
The Foresight Briefs are published by the United Nations Environment Programme to highlight a hotspot of environmental change, feature an emerging science topic, or discuss a contemporary environmental issue. The public is provided with the opportunity to find out what is happening to their changing environment and the consequences of everyday choices, and to think about future directions for policy. The 29th edition of UNEP’s Foresight Brief explores the use of plastic in agriculture and the significant waste problem this entails which impacts on soil health, biodiversity, productivity and food security.
Abstract
Plastics are used extensively in farming, from plastic coated seeds to mulch film. They also make their way into biosolid fertilizer which is spread on fields. All these products have helped increase crop yields, but there is increasing evidence that degraded plastics are contaminating the soil and impacting biodiversity and soil health. This can lead to reduced productivity and could threaten long-term food security. As a finite resource which is under pressure, agricultural soil needs to be safeguarded from further degradation. Steps are being taken to improve the production and management of agricultural products containing plastics but there is also a need to look at a more holistic approach to food production, including nature-based solutions.
Introduction
The low cost and vast range of available plastic products has changed agricultural production from a traditionally low-waste activity to an industry with a significant waste problem. The manufacture and marketing of new plastic products has increased plastic use. This has helped farmers increase yields and reduce food waste, but it has outpaced the development of systems and processes to reuse, recycle, effectively biodegrade, or adequately dispose of many agricultural plastics (Figure 1). And now there is increasing evidence that these plastics are polluting soils (Rillig 2012). Agricultural plastics are part of the broader, global problem of plastic pollution, including in the marine environment, analyzed in detail in From Pollution to Solution: A Global Assessment of Marine Litter and Plastic Pollution (UNEP 2021).
Plastic particles found in the soil can come from the breakdown of plastic products (such as containers, mulch film, plastic silage wrap, greenhouse tunnels, etc.) or from the use of products contaminated with plastic particles (such as compost or sewage sludge which contains microplastics that enter wastewater treatment plants e.g., from washing of clothing and abrasion of tyres). Plastic that ends up in soil varies in size from macroplastics (>5 mm) to microplastics (<5 mm) and nanoplastics (<1 μm) (Joint Group of Experts on the Scientific Aspects of Marine Pollution [GESAMP] 2019).
The full study is available here to view or download (PDF)
